magic_numbers

README

go-mnd - Magic number detector for Golang

A vet analyzer to detect magic numbers.

What is a magic number?
A magic number is a numeric literal that is not defined as a constant, but which may change, and therefore can be hard to update. It's considered a bad programming practice to use numbers directly in any source code without an explanation. It makes programs harder to read, understand, and maintain.

Project status

Install

This analyzer requires Golang in version >= 1.12 because it's depends on the go/analysis API.

go get github.com/tommy-muehle/go-mnd/cmd/mnd

To install with Homebrew, run:

brew tap tommy-muehle/tap && brew install tommy-muehle/tap/mnd

On Windows download the latest release.

Usage

go vet -vettool $(which mnd) ./...

or directly

mnd ./...

The -checks option let's you define a comma separated list of checks.

Checks

By default this detector analyses arguments, assigns, cases, conditions, operations and return statements.

• argument

t := http.StatusText(200)

• assign

c := &http.Client{
    Timeout: 5 * time.Second,
}

• case

switch x {
    case 3:
}

• condition

if x > 7 {
}

• operation

var x, y int
y = 10 * x

• return

return 3

Notices

By default the number 0 is excluded!

License

The MIT License (MIT). Please see LICENSE for more information.

Documentation

Index

• Constants
• Variables
• type Checker
• type Config
  • func DefaultConfig() *Config
  • func WithOptions(options ...Option) *Config
  • func (c *Config) IsCheckEnabled(name string) bool
• type Option
  • func WithCustomChecks(checks string) Option

Constants

const Doc = `magic number detector`

Variables

var Analyzer = &analysis.Analyzer{
	Name:             "mnd",
	Doc:              Doc,
	Run:              run,
	Flags:            options(),
	Requires:         []*analysis.Analyzer{inspect.Analyzer},
	RunDespiteErrors: true,
}

Types

type Checker

type Checker interface {
	NodeFilter() []ast.Node
	Check(n ast.Node)
}

type Config

type Config struct {
	Checks map[string]bool
}

func DefaultConfig

func DefaultConfig() *Config

func WithOptions

func WithOptions(options ...Option) *Config

func (*Config) IsCheckEnabled

func (c *Config) IsCheckEnabled(name string) bool

type Option

type Option func(config *Config)

func WithCustomChecks

func WithCustomChecks(checks string) Option